The most haunting music you ever heard?

I nominate "Ghost in the wind" by Richard Thompson. Especially the cut on his dvd "Live in Austin"

James Taylor singing "Overcoat" on Jerry Douglas' "Look Out For Hope" is both sad and haunting.

Dory Previn (anybody remember her?) "Doppleganger" This one really gave me the willies every time a buddy played it during my college "daze"

I think "Yulunga" from Dead Can Dance "Into the Labyrinth" fits this category too.

One of my neighbors was playing some spooky music on their porch for halloween.

Grace by Jeff Buckley.

Johnny Cash- American V - deserves a mention.